The present invention relates to an evaporator device and particularly, although not exclusively, to an air freshener device.
One existing type of air freshener comprises a bottle, filled with a liquid perfume, which bottle is fitted with a wick, which extends out of the bottle. Heat is applied to the wick with an annular electrical heater causing the perfume to evaporate.
A problem with this type of air freshener is that it is not possible to regulate the rate of evaporation of perfume. A modified type of air freshener, which attempts to address this problem, is described in Spanish Utility Model U9002819Y. In this air freshener the annular heater is movable in a direction parallel to the axis of the wick, with the aim of controlling the amount of heat applied to the wick and, hence, the rate of evaporation of the perfume. However, in practice it has been found that this arrangement does not afford much regulation of the rate of evaporation. The output of the air freshener tends to be xe2x80x9call or nothingxe2x80x9d with very little variation in between, depending upon whether the heater overlaps or is axially displaced from the wick.
It is an object of the present invention to overcome, or at least mitigate, the above mentioned problems by providing an evaporator device which enables improved regulation of the rate of evaporation of liquid.
According to a first embodiment of the present invention there is provided an evaporator device adapted to receive a container for containing a liquid. The container is provided with a wick, part of which is disposed in the container and part of which extends outside of the container. The device is characterized in that it comprises a shield which partially covers the part of the wick which is outside of the container, when present, and a heater for heating the part of the wick which is outside of the container, when present. The heater is relatively movable between a first relative position, where the shield is disposed between the heater and wick, when present, and a second relative position, where the shield is not so disposed, so as to enable the supply of heat from the heater to the wick, when present, to be regulated.
According to a second embodiment of the present invention there is provided an evaporator device adapted to receive a container for containing a liquid. The container is provided with a wick, part of which is disposed in the container and part of which extends outside of the container, and a shield which partially covers the part of the wick which is outside of the container. The device is characterized in that it comprises a heater for heating the part of the wick which is outside of the container, when present. The heater is relatively movable between a first relative position, where the shield is disposed between the heater and wick, when present, and a second relative position, where the shield is not so disposed, so as to enable the supply of heat from the heater to the wick, when present, to be regulated.
According to a third embodiment of the present invention there is further provided an evaporator device comprising a container for containing a liquid, a wick, part of which is disposed in the container and part of which extends outside of the container, a heater for heating the part of the wick which is outside of the container, and a shield. The heater is relatively movable between a first relative position, where the shield is disposed between the heater and wick, and a second relative position, where the shield is not so disposed, so as to enable the supply of heat from the heater to the wick to be regulated.
The evaporator device is preferably used to evaporate an active agent in liquid form.
Suitable solvents for the active agent include water, alkyl alcohol, e.g., isopropanol or ethanol, an ether (such as monopropylene glycol methyl ether, dipropylene glycol methyl ether and/or tripropylene glycol methyl ether), carbitol, a glycol (such as propylene glycol or dipropylene glycol).
The active agent preferably comprises a perfume and, optionally, a malodor counteractant and/or an insecticide.
A suitable perfume for use in the invention comprises one or more fragrant materials, such as cedarwood oil, sandalwood oil, bergamot, Bulgarian rose oil, patchouli, myrrh, clove leaf oil, linalol, ethyl alcohol, terpineol, menthol, citronellal, and/or phenyl ethyl alcohol.
A suitable deodorant for use in the invention is one or more aroma and/or non-aroma chemicals which are known to have an action in reducing the perception of the intensity of malodors, e.g., unsaturated esters, ketones, aldehydes, and/or a fragrant material, e.g., citronellal and/or cedarwood oil (which is known to counteract the perception of tobacco malodor).
A suitable insecticide for use in the invention comprises one or more of the natural insecticides, such as a pyrethroid, nicotinoid, rotenoid, and/or one or more of the synthetic insecticides, e.g., tetramethrin, bioallethrin, allethrin, phenthrin, a dinitrophenol, an organothiocyanate, benzene hexachloride, a polychlorinated cyclic hydrocarbon (e.g., heptachlor, aldrin and/or telodrin), and/or an organophosphorous (e.g., tetraethyl pyrophosphate).
The active agent may further comprise an antioxidant, such as tocopherol, ascorbyl palmitate, butylated toluene, ascorbic acid, tert-butyl hydroquinone, beta-carotene, and/or a gallate. In addition, the active agent may optionally comprise a UV stabilizer, such as Uvinol(trademark) 400.
A suitable container for the liquid is one made from a water/organic solvent-insoluble material, which is optionally either a plastic material, for example, polypropylene, HDPE (high density polyethylene), PET (polyethylene terephthalate), or Barex(trademark) or, preferably, glass A. Suitable wick is made, for example, from a natural or synthetic fibrous material, such as cotton, fiberglass, mineral fibers, cellulose, ceramic, graphite or polyester.
The shield is preferably arranged such that it surrounds a portion of the exposed part of the wick, when present. As such, it is preferred that the shield is in the form of a tube through which a portion of the exposed part of the wick may extend. The shield is preferably substantially annular in cross-section, although other configurations may be employed.
The heater is preferably generally annular, defining an aperture. It is preferably arranged to be movable in a direction generally parallel to the axis of the wick, when present. When a container provided with a wick is inserted into the device, the wick preferably extends through the aperture defined by the heater.
Where the shield comprises a tube, through which a portion of the wick extends when present, the aperture through the heater is preferably of sufficient size to enable the heater to pass over the shield. As such, it will be appreciated that the wick, shield and heater can be arranged so that the heater may be moved along the axis of the wick. Thus, at one position the shield lies between the heater and wick, reducing the heat flow from the heater to the wick, and at another position the heater is directly exposed to the wick to obtain maximum heat flow to the wick. In intermediate positions, the heater is partially shielded from the wick allowing the flow of heat to be regulated between the two extremes.
In order to afford even greater regulation of the amount of heat supplied to the wick, the thickness of the shield preferably varies in the direction in which relative movement of the heater can be made. The thinner the shield, the more heat it will transmit and vice versa. The thickness of the shield could vary continuously to enable continuous variation of heat flow to the wick, or alternatively it could vary in steps to give a number of discrete levels.
The heater is preferably an electrical element formed into a ring shape, for example a torroidally wound resistor wire or a P.T.C. element. The heater may be encased in a plastic material. The heat output of the heating means is preferably suitable to give a running temperature of from about 50 to about 120xc2x0 C., more preferably from about 60 to about 80xc2x0 C., most preferably about 70xc2x0 C.
The device according to the invention is preferably an electrical device. The electrical power supply is optionally either in the form of batteries or, preferably, the electrical device is adapted to be connected to an electrical power supply, e.g., a domestic mains socket.
Preferably, the device comprises a housing which is adapted to support the heater, the housing preferably including one or more apertures to allow the perfume or other vapor to escape. The housing is preferably formed from a plastic material, for example polypropylene.
In one arrangement the device and, particularly, the housing comprise the shield. Preferably, the shield is formed integrally with the housing. This arrangement has the advantage of being economical to manufacture, as no separate component is required.
In another arrangement the shield is formed separately, for example as part of the container.
Preferably, the shield forms part of a plug for retaining the wick in the container. This arrangement allows the shield to be formed from a different material than the remainder of the device. This would allow the wick to be formed from a heat insulating material to give improved control over the flow of heat, rather than being restricted to the material from which the housing is constructed.
Preferably, the device is provided with an external control, which regulates the relative movement of the heater. This is in order that the user is able to adjust the rate of evaporation of liquid. The control may, for example, comprise a wheel, which may optionally be graduated. The device according to the invention is preferably provided with an actuating means, e.g. a switch, to control operation of the device. More preferably, this actuating means forms part of the external control.
The provision of a shield, particularly one of varying thickness, enables improved control over the flow of heat from the heater to wick, and hence over the rate of evaporation of liquid, compared to known devices. The invention allows the user to adjust the vapor output of the device progressively between a maximum and minimum level, for example depending on the size of the room in which the device is installed.